A composite material is composed of at least two distinct constituent materials or phases, that when combined have physical properties unlike the individual phases. The physical properties of a composite material are determined by the physical properties of the constituent materials, the volume or mass ratio of each phase, the interface properties between each of the phases, and the geometry of the phases. This invention disclosure is related to the relative geometry of the constituent phases.
The constituent phases of a two-phase composite material are commonly termed for their mechanical function, i.e. reinforcement phase and matrix phase. The reinforcement phase provides the majority of the mechanical support while the matrix phase distributes the load between/to the reinforcement phase. Reinforcement materials are commonly in the form of particles, short fibers, or continuous fibers, and the bulk mechanical properties of a composite material can range from isotropic to highly anisotropic depending on the shape and orientation of the reinforcement phase; however, these common reinforcement materials do not constitute a continuous phase. The matrix phase is, by definition, the only continuous phase in these types of composites. Although much of the work in composite materials is related to the mechanical properties, other physical properties are of importance and are also a function of the geometry of the constituent phases. For example, theoretical studies have been done to determine the optimum geometry for a two-phase composite to maximize both thermal and electrical conductivity. See Torquato et al., “Multifunctional Composites: Optimizing Microstructures For Simultaneous Transport Of Heat And Electricity,” Phys. Rev. Lett. 89, 266601 (2002), Issue 26, the entire content of which is incorporated herein by reference.
Work has also been done on creating various forms of composite materials with two interpenetrating, yet distinct continuous phases. These include materials where one phase is an open cellular foam—derived from a material such as a polymer, ceramic, or metal—and then infiltrated with a dissimilar material to create a composite. See Klett et al., “Pitch-Based Carbon Foam And Composites And Use Thereof,” U.S. Pat. No. 7,070,755, Jul. 4, 2006; Grylls et al., “Article Made Of A Ceramic Foam Joined To A Metallic Nonfoam, And Its Preparation,” U.S. Pat. No. 6,582,812, Jun. 24, 2003; Rettenbacher et al., “Multilayer Composite Armour,” U.S. Pat. No. 7,026,045, Apr. 11, 2006; Williams et al., “Composite Foam Structures,” U.S. Pat. No. 6,929,866, Aug. 16, 2005; Terasaki et al., “Metal-Ceramics Composite, Heat Dissipation Device Employing It, And Processes For Producing Them,” U.S. Pat. No. 6,399,187, Jun. 4, 2002; and Zeschky et al., “Preceramic Polymer Derived Cellular Ceramics,” Composites Science and Technology, Vol. 63 (2003) 2361-2370; the entire contents of each of which are incorporated herein by reference. Related composites with multiple co-continuous phases may also include materials formed from immiscible block-copolymers. See Epps et al., “Network Phases In ABC Triblock Copolymers,” Macromolecules, Vol. 37 (2004) 7085-7088 and Daoulas et al., “Fabrication Of Complex Three-Dimensional Nanostructures From Self-Assembling Block Copolymer Materials On Two-Dimensional Chemically Patterned Templates With Mismatched Symmetry,” Physical Review Letters, Vol. 96 (2006) 036104; the entire contents of each of which are incorporated herein by reference. However, the above discussed composite structures do not provide for a composite structure with two interpenetrating phases where one phase maintains a truss-like 3D ordered microstructure derived from a 3D pattern of polymer optical waveguides.
As such, there is a need for a composite structure with two interpenetrating phases where one phase maintains a truss-like 3D ordered microstructure derived from a 3D pattern of polymer optical waveguides.